Sorry if this has been posted, but I don't have time to search.

Ok, yesterday, the computer was working fine, then my brother, instead of going start > turn off, he held down the power button to turn off the computer.

This morning, we entered in our login information, hit enter, and the pc restarted.

Is it possible something is overheating?

Any help is appreciated.

Hmm you dont have the time to make a decent post either, come on give us some more info

Does it do it everytime you logon, was it just the once, have you tried safe mode, or similar, what have you done (apart from post here) to try and fix it.?

Regards

Win2000 or XP?
Does safe mode work?
etc

I just did a system recovery, it works now.

It is probably blue screening. "Last known good configuration" probably would have worked.
I would turn off Automatic Restart, just in case so you can catch the error message if it happens in the future.

1.Right-click My Computer, and then click Properties.
2.Click the Advanced tab.
3.Under Startup and Recovery, click Settings to open the Startup and Recovery dialog box.
4.Clear the Automatically restart check box, and click OK the necessary number of times.

Pity you didnt try that before posting,

Regards